Sound of "splashing a water in half-full big bottle"

Couple of days ago we had a huge rain. Next day, when I was driving, I was able to hear a clear sound similar to "splashing a water in half-full big bottle". I stopped and went around the car. On right side, right between front and back passenger's doors, there was a steady leak of water. I have checked inside the cabin for any water and found none. No smell either.

There should be drains on each side of the cowl grill, below the wipers. You should be able to see them when you pop the hood. (at least you can on my 2005). Does is have a sun roof? there are drain tubes that run down from the front corners of the track area, down the "A" pillar and out by the bottom of the door up near the hinge .

Hi guys,
I have checked all doors found no holes or drains in them. Also, no holes or drains in steps. I have checked the sun-roof. And there two drain holes.
I'll check with dealer tonight and I'll let you know.
Thanks.